The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 26, 2008
Filed:
Mar. 02, 2006
Shinji Ohta, Shizuoka, JP;
Masayasu Ito, Shizuoka, JP;
Shinji Ohta, Shizuoka, JP;
Masayasu Ito, Shizuoka, JP;
Koito Manufacturing Co., Ltd., Tokyo, JP;
Abstract
A DC/AC converterperforms AC conversion and a boosting function upon the reception of a DC voltage. A control unitcontrols the DC/AC converterto perform the lighting control of a discharge lamp. The DC/AC converter includes an AC conversion transformer, switching devicesH,L and a resonance capacitor, and drives the switching devices to produce series resonance in the capacitorand an inductance component for the transformeror the inductance device. Before the discharge lampis turned on, the drive frequency for the switching devices gradually nears a resonance frequency fto increase an unloaded output, and a start signal is supplied to the discharge lamp. After the lighting of the discharge lamp has been initiated, the drive frequency is defined that is higher, by a predetermined frequency displacement value ΔF, than the drive frequency immediately before the discharge lamp is turned on. And the drive frequency for the switching device is shifted to a frequency area fb that is higher than a resonance frequency fwhen the discharge lamp is turned on.